Approaches to the preparation of 3'-deoxynucleosides

Abstract

The stability of 3'-O-sulphonyl derivatives of uridine towards nucleophilic displacement indicates that sulphonate replacement is unlikely to offer a general route to 3'-deoxynucleosides. The preparation of 3'-deoxyuridine by direct iodination of 2',5'-di-O-trityluridine with triphenylphosphite methiodide followed by catalytic hydrogenolysis is discussed as such a general route dependent on the availability of suitably protected nucleoside starting materials. Acyl migration takes place under the conditions of the iodination reaction, limiting the choice of protecting groups.